sci.electronics.repair@googlegroups.com

Google Groups

N_Cook <diverse@tcp.co.uk>: Feb 09 12:41PM Excessive hiss above 1/3 vol or so. Change U1 first opamp at input, LF353, to something low noise or some other known cause. When trying it out, the hiss peaked for a while, then dropped back, not returning on twizzling. Not tried heating/cooling yet

tenyen@gmail.com: Feb 08 03:21PM -0800 Heya,   TL;DR: stumbled here via: http://www.pssurvival.com/PS/Electronic/Repair/Troubleshooting_And_Repair_Of_Consumer_Electronics_Equipment_2004.pdf which was posted to the mailing list of the http://therestartproject.org/ and I like what I see so far, more below . . .   On Saturday, 7 February 2015 20:23:17 UTC, Adrian Caspersz wrote: > > On Friday, January 30, 2015 at 3:56:53 AM UTC-5, RAJESH KUMAR wrote: > >> hiiii frnd im new in this group im need schematic diagram 10203-1 b560 laptop   > > The brand might help, but really you don't usually get schematics for computers. Fact is, the way they are, all you can do is change regulators and capacitors.   there's also reflow'ing; "we" see a few laptops (particularly with nvidia chipsets) where this might be an issue.   > Then some of them (in the words of a mobo manual I read years agho) "hang permanently when the errors introduced by dirty power corrupts the BIOS past being able to flash. If it won't boot it won't flash.   then it might be worth using SPI or JTAG or similar . . .   > host free recent laptop schematics (pinched from the factory?). Takes a > bit of googling.   > Start with the word kythuatvitinh and don't do it from a Windows machine.   "Computer Technician" apparently . . I *love* a "shady" tip . . .   walk on the wild side ;)   -- http://tenyen.net/

mike <ham789@netzero.net>: Feb 08 04:58PM -0800 > there's also reflow'ing; "we" see a few laptops (particularly with nvidia chipsets) where this might be an issue. Got any more precise tips in that area? Temperatures and times and ramp rates etc. What's a good air temperature to use?   Lots of youtube videos, but not any detail on the numbers involved.   I built a fixture with a heat gun pointed at the bottom and another one on top. Managed to fix two of the three I tried. But it would be nice to have a better idea on optimum strategy. I have thermocouples on top and bottom, but Have not figured out how to couple the thermocouple to the chip. Any stress will cause the chip to move when the solder melts...not good.

sam@repairfaq.org (Samuel M. Goldwasser): Feb 08 04:17PM -0500 > One more point, during this 4 seconds, the ovan is noisy as usual. But > after it failed, it is quiet but the cooling fan is still turning.   There isn't much besides the rectifier, inverter, and magnetron.   That tick tick might be the inverter trying to power an excessive load - just a guess.   Magnetrons can fail with voltage applied and test good on a meter.   You can probably find a new/NOS replacement for less than $20 on eBay.   It's worth the risk. :)   -- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html   Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

captainvideo462009@gmail.com: Feb 08 10:47AM -0800 On Thursday, October 17, 2013 at 7:55:39 PM UTC-4, Dan wrote: > trying to sell fuses, not any giving how to read the ratings.   > TIA   > Dan   I've probably had a few thousand TV's come in here over the years. (not any more). NAP sets seemed to use circuit breakers a lot. Some other brands I recall that had open B+ fuses smoked and then blew the fuse when a new one was installed for testing. Often wondered why it didn't smoke the first time before the first fuse opened. Lenny

mogulah@hotmail.com: Feb 08 08:59AM -0800 Bleeding 7-segment LCD displays, explained   On Sunday, February 8, 2015 at 9:35:56 AM UTC-5, N_Cook wrote in sci.electronics.repair:   > I've brought along , what I often see in repairing electronic stuff, > black bleeding within a 7-segment LC display. All I know is the problem > seems to develop from being excessively cold or hot   I never knew that excessive cold (absent moisture) could hurt electrical functions.

mogulah@hotmail.com: Feb 08 09:34AM -0800 On Sunday, February 8, 2015 at 12:19:13 PM UTC-5, Lloyd E. Sponenburgh wrote:   > Live and learn, huh?   > Yeah, LCDs are more-or-less adversely affected by temperature, at both > ends.   Well, and on another note, I guess the car battery is rather weak starting up the car when its cold, too.

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.